Sim,
Are you familiar with “area ruling”?
Where you pick up the wings and out riggers, the fuselage needs thinned.
If you take and cut up the car into 4” thick slices cross wise, then measure those cross sections and graph them, the graph should be smooth. This is important. We could have done a better job with this on the Carbiliner.
Flat sides are always bad even if it adds to frontal area.
You will always be more slippery if shape is changed gradually. IE your wheel pants should be shaped like airfoils.
Eric “Blue” was right when he steered us to the NACA 66 series airfoil. It is extremely efficient in terms of volume vs drag.
The wetted area of car that is laminar flow is only 1/3 of the drag of the wetted area not in laminar flow.
Believe it or not, if you would swell the sides of the car and shorten it, the drag should go down even though frontal area is increased.
You should also be able to lose the supports for the wheel pants by increasing cross section of the wing.
Those supports will be extremely draggy.
With the downforce in the rear, you will not need rear suspension. At least that has been my experience.
Rob Freyvogel
#496
AA/BFS
My original body based on the Sears Haack profile was a perfect spherical arch from nose to tail. The length of the design currently is largely dictated by the power train and component systems. Your point about the bracing is well taken and gave me an idea how to eliminate them all together as seen in the drawings below.
By moving the wheel motors outboard with the wheels we can eliminate the need for axles between the chassis and the wheels. The wheel pods and flat wing structure would be a one piece molded carbon composite that saddles across the chassis just like the wing on a sport plane. Access to the wheels would be through removable covers (not shown) on the outboard side of the pods. The wheel motors would bolt to the pod from the backside above the wing (black circle) with the wheels bolted conventionally to the motor faces.
The flaps would work the same as before but here they're mounted down on the deck. I think they would be just as effective for generating downforce in this position. Cp would be well back of center line and my guess is that Cd would be much lower as well even with the added frontal area. I have no doubt the structural integrity of the the design would be maintained using this outboard wheel/motor arrangement.
